Overexpression of SLC35F2 is a potential prognostic biomarker for lung adenocarcinoma

Objective

To explore the potential clinical and prognostic significance of Homo sapiens solute carrier family 35 member F2 (SLC35F2) in the context of lung adenocarcinoma (LUAD).

Methods

The expression pattern of SLC35F2 in LUAD tissues and normal tissues was analyzed in The Cancer Genome Atlas (TCGA) datasets and validated in 12 pairs of fresh clinical LUAD tissues and their corresponding adjacent normal tissues using quantitative real-time PCR (qRT-PCR) and western blotting. Immunohistochemistry (IHC) was used to assess the protein expression of SLC35F2 in 60 paraffin-embedded LUAD tissues, and its associations with clinicopathological parameters were further examined. The prognostic significance of SLC35F2 mRNA expression was also evaluated using the Kaplan-Meier method, and Cox regression models in LUAD patients from the TCGA database. The potential utility of SLC35F2 as an indicator of recurrence or metastasis was explored through the follow-up of selected clinical LUAD cases. Lastly, gene set enrichment analysis (GSEA) was conducted to investigate the underlying biological mechanisms and signaling pathways.

Results

Bioinformatics analysis utilizing the TCGA database indicated that SLC35F2 mRNA exhibited heightened expression in LUAD tissues when compared to normal tissues. These findings were further substantiated through the examination of 12 pairs of clinical LUAD tissues and their corresponding adjacent normal tissues, employing qRT-PCR and western blotting techniques. IHC results from a cohort of 60 LUAD patients demonstrated an up-regulation of SLC35F2 in 38 out of 60 individuals (63.3 %), which exhibited a significant correlation with tumor size, lymph node metastasis, and clinical stage (all P < 0.05). Both the Kaplan-Meier curve and the Cox proportional hazard analyses indicated a strong association between the up-regulation of SLC35F2 mRNA expression and unfavorable overall survival (OS) in patients with LUAD, as observed in the TCGA datasets (P < 0.05). The follow-up findings from select clinical LUAD cases provided evidence that the expression of SLC35F2 could serve as a dependable biomarker for monitoring the recurrence or metastasis. Additionally, the GSEA highlighted the enrichment of apoptosis, adhesion, small cell lung cancer (SCLC), and p53 signaling pathways in the subgroup of LUAD patients with elevated SLC35F2 expression.

Conclusion

SLC35F2 exhibited an up-regulated in both mRNA and protein expression, rendering it a valuable independent prognostic indicator for patients diagnosed with LUAD.

Characterizing the cancer-associated microbiome with small RNA sequencing data

The microbiome is recognized as a quasi-organ in the human body. When dysbiosis of the microbiome occurs, this variation may contribute to alterations in the microenvironment, potentially inducing an inflammatory immune response and providing a niche for neoplastic growth. However, there is limited evidence regarding the correlation and interaction between the microbiome and tumorigenesis. By utilizing microRNA sequencing data of patients with colon and rectal cancer from The Cancer Genome Atlas, we designed a novel analytical process to extract non-human small RNA sequences and align them with the microbial genome to obtain a comprehensive view of the cancer-associated microbiome. In the present study, we identified >1000 genera among 630 colorectal samples and clustered these samples into three distinctive colorectal enterotypes. Furthermore, we found 12 genera from these clusters that are associated with cancer stages and revealed their putative functions. Our results indicate that the proposed analytical approach can effectively determine the cancer-associated microbiome. It may be readily applied to explore other types of cancer, in which specimens of the microbiome are difficult to collect.